1. Field of the Invention
Apparatus including an electroacoustic transducer having terminal contacts which extend in the direction of the transducer axis and including a printed circuit board having mating contacts.
The invention relates to an apparatus having a housing and an electroacoustic transducer accommodated in the housing, the transducer having a diaphragm, a moving coil connected to the diaphragm, and a magnet system adapted to cooperate with the moving coil, the magnet system being coaxial with a transducer axis of the transducer, and surrounding an inner space which is coaxial with the transducer axis, and the transducer having two terminal contact elements each serving for the electrically conductive connection to a moving coil lead of the moving coil, and being disposed at least partly inside the inner space in the magnet system, and extending at least partly parallel to the transducer axis, and the apparatus further including a printed circuit board accommodated in the housing and provided with two mating contacts which are each in mechanical contact with and have an electrically conductive connection to a terminal contact element.
The invention also relates to an electroacoustic transducer for use in such an apparatus.
2. Description of the Related Art
An apparatus and an electroacoustic transducer, as described above are commercially available and are consequently known. For the known constructions reference can be made to International Patent Application WO 98/38832 A1, corresponding to U.S. patent application Ser. No. 09/033,200, filed Mar. 2, 1999. In the known constructions, the electroacoustic transducer, is secured to the housing of the known apparatus with the aid of fixing means. Furthermore, the printed circuit board is also secured to the housing, or to stationary parts connected to the housing, with the aid of further fixing means. The terminal contact elements are formed by contact springs having one bend. The mating contacts are formed by conductor track areas on the printed circuit board. As long as the electroacoustic transducer is comparatively large, its outer diameter being of a magnitude larger than 10 mm, for example, between 13 mm and 40 mm, the known constructions yield satisfactory results. However, further miniaturization of an apparatus, such as the known one and an electroacoustic transducer as the known one, gives rise to problems because terminal contact elements formed by contact springs having one bend and mating contacts formed by conductor track areas on the printed circuit board establish a proper electrically conductive connection only if the construction of the housing and the construction of the printed circuit board are within comparatively narrow tolerance limits, because the terminal contact elements having one bend only enable a limited compensation for tolerances of the aforementioned type. Moreover, it is to be noted that the terminal contact elements in the form of contact springs having one bend which, as stated, have been provided in the International Patent Application WO 98/38832 A1, can be miniaturized only to a limited extent and can, therefore, no longer be used in transducers which are further miniaturized in comparison with the known transducer.
It is an object of the invention to preclude the aforementioned problems and to provide an improved apparatus and an improved electroacoustic transducer in which, also in the case of further miniaturization, always a trouble-free and substantially tolerance-independent electrical connection is obtained between two terminal contact elements of the transducer and two mating contact elements on a printed circuit board.
In order to achieve the aforementioned object, according to the invention, the apparatus as described above is characterized in that two mating contact elements are provided as mating contacts which are separate from the printed circuit board, the two separate mating contact elements being mechanically connected to the printed circuit board, and each having a mating contact portion which extends substantially parallel to the transducer axis, and a terminal contact portion which extends also substantially parallel to the transducer axis and is in contact with a mating contact portion which extends parallel to the transducer axis, the terminal contact portions and the mating contact portions being held pairwise against each other in a direction transverse to the transducer axis and thus forming at least parts of retaining means for securing the transducer to the printed circuit board.
Further in order to achieve the aforementioned object, according to the invention, the transducer as described above is characterized in that the two terminal contact elements each have a terminal contact portion which extends also substantially parallel to the transducer axis and which forms a part of retaining means for securing the transducer to a printed circuit board, this part acting in a direction which is oriented transversely to the transducer axis.
By means of the measures in accordance with the invention, it is achieved, in a simple manner and at only low cost, that between the two terminal contact elements of a transducer in accordance with the invention, and the two mating contact elements on the printed circuit board in an apparatus in accordance with the invention, always a trouble-free electrical connection which is substantially independent of component tolerances is guaranteed, also in the case that the apparatus and the transducer are comparatively small and the transducer has an outer diameter of a magnitude smaller that 10 mm, for example, of a magnitude between 5 mm and 10 mm. Moreover, it is thus achieved that an electroacoustic transducer in accordance with the invention is secured directly to the printed circuit board of an apparatus in accordance with the invention by simple means, and that the transducer in accordance with the invention can be mounted on and secured to the printed circuit board before the housing of the apparatus is closed, which has the advantage of a simple mounting and of a simple testing of the formation of the electrically conductive connections between the terminal contact elements and the mating contact elements.
In an apparatus in accordance with the invention, a terminal contact portion and a mating contact portion may cooperate with each other, for example, only under the influence of friction, and may thus be held against each other in a direction transverse to the transducer axis and thereby perform a retaining function with the aid of which the transducer in accordance with the invention is secured to the printed circuit board. However, it has very advantageous that, in addition, at least one contact portion of a contact portion pair, consisting of a terminal contact portion and a mating contact portion, is resilient in a direction which is oriented transversely to the transducer axis, because in this way, a particularly reliable electrical contact is established, and also a proper mechanical fastening of the transducer in accordance with the invention to the printed circuit board is achieved. Likewise, it has proven to be advantageous that, in the terminal contact portions are resilient in a direction which is oriented transversely to the transducer axis.
In an apparatus in accordance with the invention, it has proven to be very advantageous that the two mating contact elements consist of a material which is resistant to temperatures prevalent during soldering processes. because it is thus guaranteed that the mating contact elements can be connected to the printed circuit board both electrically and mechanically by an arbitrary solder process without any damage as a result of high-temperature effects.
In an apparatus in accordance with the invention, two mating contact elements may be provided, which are each mechanically connected to the printed circuit board without any further means. However, it has proven to be particularly advantageous that, in an apparatus in accordance with the invention, the two mating contact elements are disposed, at least for the greater part, in a mating contact element holder at least in the area of their mating contact portions, and the mating contact portions are arranged to be accessible for the terminal contact portions of the terminal contact elements without being hindered by the mating contact element holder, and the mating contact element holder is mechanically connected to the printed circuit board. This results in a very high mechanical stability and a proper protection for the mating contact elements.
In an apparatus in accordance with the invention having a mating contact element holder, it has proven to be particularly advantageous that the printed circuit board has a hole which traverses the printed circuit board, and the mating contact element holder is mounted in the hole, because such a construction has a particularly small overall height in the direction of the transducer axis of the transducer.
In an apparatus in accordance with the invention as mentioned in the preceding paragraph, it has proven to be particularly advantageous that, in addition, the mating contact element holder mounted in the hole of the printed circuit board is connected to the printed circuit board by means of a press-fit, because this results in a particularly simple mechanical connection between the mating contact element and the printed circuit board.
In an apparatus in accordance with the invention having a mating contact element holder, it has further proven to be advantageous that, in addition, each mating contact portion has a solder portion for connecting the mating contact portion to a conductor track area of the printed circuit board in an electrically conductive manner with the aid of a soldered joint. Thus, it is simply possible to form both an electrically conductive connection and a mechanically stable connection between each mating contact element and a conductor track area of the printed circuit board.
In an apparatus in accordance with the invention it has further proven to be particularly advantageous that, in addition, the two terminal contact elements are disposed, at least for the greater part, in a terminal contact element holder at least in the area of their terminal contact portions, and the terminal contact portions are arranged to be accessible for the mating contact portions of the two mating contact elements without being hindered by the terminal contact element holder, and the terminal contact element holder is connected to the magnet system of the transducer inside the inner space of the magnet system. Such a construction also provides a high mechanical stability and a proper protection for the terminal contact elements of a transducer in accordance with the invention. Likewise, it has proven to be advantageous, in a transducer in accordance with the invention, that the two terminal contact elements are disposed, at least for the greater part, in a terminal contact element holder at least in the area of their terminal contact portions, and the terminal contact portions are arranged to be accessible without being hindered by the terminal contact element holder, and the terminal contact element holder is connected to the magnet system of the transducer inside the inner space of the magnet system.
In an apparatus in accordance with the invention, it has proven to be highly advantageous that, in addition, the mating contact element holder and the terminal contact element holder form parts of mechanical retaining means for retaining the transducer on the printed circuit board, and the terminal contact portions of the two terminal contact elements and the mating contact portions of the two mating contact elements in addition form parts of said retaining means and enhance the retaining function of the mating contact element holder and the terminal contact element holder, because in this way the mating contact element holder and the terminal contact element holder are used not only to support and protect the mating contact elements and the terminal contact elements but also to secure a transducer in accordance with the invention to the printed circuit board of an apparatus in accordance with the invention in a stable and reliable manner. Likewise, it has proven to be highly advantageous, in a transducer in accordance with the invention, that the terminal contact element holder forms a part of mechanical retaining means for retaining the transducer on a printed circuit board, and the terminal contact portions of the two terminal contact elements in addition form parts of said retaining means and enhance the retaining function of the terminal contact element holder.
In an apparatus in accordance with the invention of the construction mentioned in the preceding paragraph, it has further proven to be very advantageous that, in addition, the terminal contact element holder is plugged onto the mating contact element holder, and the two element holders are held together under the influence of friction, results in a satisfactory and trouble-free retaining function as well as a high degree of simplicity.
In an apparatus in accordance with the invention, it has further proven to be very advantageous that, in addition, the terminal contact element holder, in addition, is adapted to retain the parts of the magnet system of the transducer axially and to position said parts radially. Likewise, it has proven to be very advantageous, in a transducer in accordance with the invention, that the terminal contact element holder, in addition, is adapted to position the parts of the magnet system of the transducer radially. This because in this case the terminal contact element holder performs additional function, which is advantageous for a simplified construction.
In an apparatus in accordance with the invention it has proven to be particularly advantageous that, in addition, the two terminal contact elements and the two mating contact elements are arranged to be coaxial with each other. Likewise, it has proven to be particularly advantageous, in a transducer in accordance with the invention, that the two terminal contact elements are arranged to be coaxial with each other. These coaxial constructions are of particularly great advantage because it is thus achieved, in a very simple manner, that, during mounting of the transducer in accordance with the invention on the printed circuit board of an apparatus in accordance with the invention, the transducer need not be in a well-defined position, but the transducer can be placed with terminal contact elements onto the mating contact elements of the printed circuit board in an arbitrary angular position of the transducer with respect to the printed circuit board.
The above-mentioned as well as further aspects of the invention will become apparent from the examples of embodiments described hereinafter and will be elucidated with reference to these examples.